diff --git a/config/config.sample.php b/config/config.sample.php
index 2aa240afe2..d0332cc228 100755
--- a/config/config.sample.php
+++ b/config/config.sample.php
@@ -172,6 +172,10 @@ $CONFIG = array(
 /* File for the owncloud logger to log to, (default is ownloud.log in the data dir) */
 "logfile" => "",
 
+/* This entry is just here to show a warning in case somebody copied the sample configuration. DO NOT ADD THIS SWITCH TO YOUR CONFIGURATION!  */
+/* If you, brave person, have read until here be aware that you should not modify *ANY* settings in this file without reading the documentation */
+"copied_sample_config" => true,
+
 /* Loglevel to start logging at. 0=DEBUG, 1=INFO, 2=WARN, 3=ERROR (default is WARN) */
 "loglevel" => "",
 
diff --git a/lib/base.php b/lib/base.php
index 1f3c616fb1..f2c66222ef 100644
--- a/lib/base.php
+++ b/lib/base.php
@@ -567,6 +567,18 @@ class OC {
 				OC_Util::addScript('backgroundjobs');
 			}
 		}
+
+		// Check whether the sample configuration has been copied
+		if(OC_Config::getValue('copied_sample_config', false)) {
+			$l = \OC_L10N::get('lib');
+			header('HTTP/1.1 503 Service Temporarily Unavailable');
+			header('Status: 503 Service Temporarily Unavailable');
+			OC_Template::printErrorPage(
+				$l->t('Sample configuration detected'),
+				$l->t('It has been detected that the sample configuration has been copied. This can break your installation and is unsupported. Please read the documentation before performing changes on config.php')
+			);
+			return;
+		}
 	}
 
 	private static function registerLocalAddressBook() {